Late Bloomers

It’s the time of year when, sadly, only a few wildflowers are still in bloom. As the summer rolls into August, the flowers that dazzled us in June and July wither and go to seed. This may be a small loss to us people, but there’s a huge group of animals that depend on blooming flowers for survival: insects.

A robber fly devours a wasp. Robber flies are agile predators that often target insects drawn to flowers.

A tree cricket munches on goldenrod petals.

A crab spider uses her camouflage to ambush pollinators in a goldenrod.

A bumblebee settles down for the night on Dotted Blazingstar (Liatris punctata).

Countless insects depend on flowers for nectar, pollen, and petals for food. They include bees, butterflies, beetles, wasps, tree crickets, ants, hemipterans, thrips, and more. After plants, they are the the foundation of the food web. So what do they do in late summer when wildflowers are scarce?

Fortunately for our six-legged friends, there is a small group of flowers that bravely bloom in the heat and drought of August and September. In Gallatin County, the two most obvious are Dotted Blazingstar (Liatris punctata) and Stiff Goldenrod (Oligoneuron rigida).

If you haven’t taken a close look at these plants, you’re missing out. Not just because they’re beautiful, but because their colorful petals often hold amazing dramas of sex and violence. In this post I am going to share one with you. First, let me introduce our protagonist: the American Jagged Ambush Bug (Phymata americana).

The American Jagged Ambush Bug (Phymata americana), yellow and black morphs (female and male?). Note the tubular mouthparts of the yellow individual, which are usually folded underneath the belly.

Look closely at any Stiff Goldenrod and you’re likely to find one or more of these bugs. Their bizarre shape and color help them camouflage as they wait for pollinators to land for a drink. When pollinators come too close, ambush bugs snatch them up with their raptorial front legs (like those of a praying mantis). They subdue their prey, which are often much larger than themselves, by using their straw-shaped mouthparts to inject a paralyzing venom. Once subdued, ambush bugs contentedly sip the insides of their prey while resting on the flower.

An ambush bug consumes a moth she snatched off the flowers of Common Tansy (Tanacetum vulgare).

Last August I was watching ambush bugs on Stiff Goldenrods at Mt. Ellis Trail when I noticed a female carrying around a small male. The males of some insect species have a habit of riding around on their mates as a way of preventing other males from mating with her. The reason for this soon became very clear to me. Without warning, a big, mean, alpha ambush bug came out of nowhere and tried to pull the little male right off the female! Click on the first photo below to watch the drama unfold: